Feature Flags PHP

PostHog feature flags for PHP

This skill helps you add PostHog feature flags to PHP applications.

Reference files

• references/php.md - Php feature flags installation - docs
• references/adding-feature-flag-code.md - Adding feature flag code - docs
• references/best-practices.md - Feature flag best practices - docs

Consult the documentation for API details and framework-specific patterns.

Key principles

• Environment variables: Always use environment variables for PostHog keys. Never hardcode them.
• Minimal changes: Add feature flag code alongside existing logic. Don't replace or restructure existing code.
• Boolean flags first: Default to boolean flag checks unless the user specifically asks for multivariate flags.
• Server-side when possible: Prefer server-side flag evaluation to avoid UI flicker.

PostHog MCP tools

Check if a PostHog MCP server is connected. If available, look for tools related to feature flag management (creating, listing, updating, deleting flags). Use these tools to manage flags directly in PostHog rather than requiring the user to do it manually in the dashboard.

Framework guidelines

• Remember that source code is available in the vendor directory after composer install
• posthog/posthog-php is the PHP SDK package name
• Check composer.json for existing dependencies and autoload configuration before adding new files
• The PHP SDK uses static methods (PostHog::capture, PostHog::identify) - initialize once with PostHog::init()
• PHP SDK methods take associative arrays with 'distinctId', 'event', 'properties' keys - not positional arguments